In the vein of classic children’s literature, Doctor Who (at least Nu-WHo) has been about teaching children the harsh realities of life. Marriage is scary, but wonderful with compromise. Parents die. Babies are lost to their mothers. Adoption can be amazing. Your boyfriend can grow and change and not love you any more etc. etc. Here? Well the subtext is clearly telling children that older people (their grandparents; their parents) never truly stop being afraid of things, even if they’re not afraid of the ‘lovely’ dark. You don’t grow out of fear, so the Doctor tells us. Though, if you’re lucky you can use it to help you grow… up.
What is enchanting about text and subtext here is how it both reveals Moffat’s subconscious fears for the show, and Twelve, yet offers up a fantastic solution. At the tail end of the episode, when a young Time-lord (to be) lies shaking and shivering in his bed, Clara’s reaches out literally and figuratively and Steven Moffat shows each child watching that this ‘grey stick insect’ of a Doctor was once a little boy, just like them. Scared of failing tests, just like them. Steven Moffat reminds them that the Doctor grew up to be amazing, to use his brain, not his brawn. He grew up to be clever and wonderful and wise. If there was a child watching who, unlike Clara, still couldn’t see the Doctor after Eleven became Twelve, I assume now they can. It’s a brilliant dramatic device and use of time-travel.